The disclosure of Japanese Patent Application No. 2002-024510 filed on Jan. 31, 2002 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a gas-liquid separation device, which efficiently separates an oil mist from blow-by gas flowing into a rocker chamber, in a vibrator engine.
2. Description of the Related Art
Recently, some overhead valve (OHV) engines have been using a dip lubrication method by which a stir is provided in a crank chamber to generate a large amount of oil mist, and the oil mist lubricates moving parts provided in the crank chamber and a rocker chamber, and the inner peripheral surface of a cylinder bore. Also, the above engines have been installed with a breather device in which blow-by gas filled in the crank chamber is led to an intake system for re-combustion, using a pulsation generated in the crank chamber.
However, since a large amount of oil mist is included in the blow-by gas in the OHV engines adopting the dip lubrication method, it is required to separate the oil mist from the blow-by gas when the blow-by gas is led to the breather chamber.
Thereby, in conventional OHV engines adopting the dip lubrication method, the rocker chamber functions as a gas-liquid separation chamber, the rocker chamber and the crank chamber communicate with each other through an oil delivery passage and an oil return passage, the oil mist which has been directed through the oil delivery passage is separated from the blow-by gas after the mist is made into liquid in the rocker chamber, and the separated oil is returned to the crank chamber through the oil return passage. On the other hand, the blow-by gas is led to the breather chamber from which the gas is sent to the intake system for re-combustion, and gas-liquid separation of the gas is further performed when the gas flows into the breather chamber.
Here, a general multipurpose engine, which is under a fixed-type use, has adopted a configuration in which a breather chamber is provided at one side which is at the downstream side of an oil return passage and near a crank chamber, for example, as disclosed in Japanese Utility Patent Publication No. 6-6177.
However, when a breather chamber is provided at the downstream side of an oil return passage, satisfactory gas-liquid separation may not be obtained even by vigorous vertical vibration, for example, in an engine which is installed in a vibrator such as a rammer (hereinafter referred to as xe2x80x9cvibrator enginexe2x80x9d).
Accordingly, in the vibrator engine, the breather chamber is provided on the top of a rocker chamber, that is, at a position which is at the greatest distance from a crank chamber, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 10-176518, in order to obtain satisfactory gas-liquid separation.
However, the technology disclosed in Japanese Unexamined Patent Application Publication No. 10-176518, in which a large quantity of oil is returned from the oil return passage to the rocker chamber by vigorous vertical vibration during operation of the vibrator, the oil easily remains in the rocker chamber, and it becomes more difficult to adequately separate oil from the blow-by gas flowing into the breather chamber, has a disadvantage that the gas-liquid separation effect is reduced by half.
The object of the present invention is to provide a gas-liquid separation device which is installed in a vibrator engine and in which an amount of oil larger than a required quantity does not remain in a rocker chamber, and gas-liquid separation can be adequately performed in the rocker chamber, even when the device is installed in a vibrator, such as a rammer, with vigorous vertical vibration.
The present invention is characterized in that an oil chamber communicates with the downstream side of the oil return passage, and the oil chamber and the crank chamber communicate with each other through an oil discharge port, in a gas-liquid separation device in a vibrator engine, in which a crank chamber and a rocker chamber communicate with each other through an oil delivery passage and also through an oil return passage, a gas-liquid separation chamber, which separates blow-by gas generated in said crank chamber from oil included in said blow-by gas, is formed in said rocker chamber, and said rocker chamber and an intake system communicate with each other through a breather device.
In such a configuration, since at least one oil chamber is inserted to the downstream side of the oil return passage through which the rocker chamber and the crank chamber communicate with each other, and the oil chamber which is located at the most downstream position and the crank chamber communicate with each other through the oil discharge port, oil is prevented from flowing from the oil return passage into the rocker chamber to cause oil flow in one direction by which the oil is supplied from the oil delivery passage to the rocker chamber. Then, oil stored in the rocker chamber is returned to the crank chamber through the oil discharge port after the oil flows into the oil chamber, passing through the oil return passage.
The above and other objects, features and advantages of the invention will become more clearly understood from the following description by referring to the accompanying drawings.